food preference in land hermit crabs ( coenobita sp.) when given choice of meat or vegetables
DESCRIPTION
Food preference in land hermit crabs ( Coenobita sp.) when given choice of meat or vegetables. Whitney Jardine , Sarah Park and Nataya Smith BIOL 3401 Mount Allison University November 22, 2013. Hermit Crabs. Land hermit crabs ( Coenobita sp.) G astropod shells for protection - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Food preference in land hermit crabs ( Coenobita sp.) when given choice of meat or vegetables](https://reader035.vdocuments.mx/reader035/viewer/2022081503/56816612550346895dd95b04/html5/thumbnails/1.jpg)
Food preference in land hermit crabs (Coenobita sp.) when given choice of meat or
vegetables
Whitney Jardine, Sarah Park and Nataya SmithBIOL 3401
Mount Allison UniversityNovember 22, 2013
![Page 2: Food preference in land hermit crabs ( Coenobita sp.) when given choice of meat or vegetables](https://reader035.vdocuments.mx/reader035/viewer/2022081503/56816612550346895dd95b04/html5/thumbnails/2.jpg)
Hermit Crabs
• Land hermit crabs (Coenobita sp.)• Gastropod shells for protection• Scavengers • Locate food by olfaction
![Page 3: Food preference in land hermit crabs ( Coenobita sp.) when given choice of meat or vegetables](https://reader035.vdocuments.mx/reader035/viewer/2022081503/56816612550346895dd95b04/html5/thumbnails/3.jpg)
Purpose
• To determine food preference in hermit crabs when given choice between meat and vegetables
![Page 4: Food preference in land hermit crabs ( Coenobita sp.) when given choice of meat or vegetables](https://reader035.vdocuments.mx/reader035/viewer/2022081503/56816612550346895dd95b04/html5/thumbnails/4.jpg)
Previous Studies
• Visually orient food and conspecifics for social facilitation of foraging (Kurta 1982)
• Wide array of food (fruit, leaves, dead animals,etc.) (Burggren & McMahon 1988; Brightwell 1950)
![Page 5: Food preference in land hermit crabs ( Coenobita sp.) when given choice of meat or vegetables](https://reader035.vdocuments.mx/reader035/viewer/2022081503/56816612550346895dd95b04/html5/thumbnails/5.jpg)
Previous Studies
• Optimal foraging theory: scavengers selecting nutritionally balanced diet (Stephens & Krebs 1986)
• Negative preference induction (Thacker 1996)• King crab, Asian shore crab, squat lobster and
crayfish found to prefer meat diet (McLaughlin & Hebard 1959; Brousseau & Baglivo 2005; Karas et al. 2007; Correia 2003)
![Page 6: Food preference in land hermit crabs ( Coenobita sp.) when given choice of meat or vegetables](https://reader035.vdocuments.mx/reader035/viewer/2022081503/56816612550346895dd95b04/html5/thumbnails/6.jpg)
Hypotheses
• Spend greatest proportion of time in meat zone
• More likely to spend more time in the zone with conspecifics
![Page 7: Food preference in land hermit crabs ( Coenobita sp.) when given choice of meat or vegetables](https://reader035.vdocuments.mx/reader035/viewer/2022081503/56816612550346895dd95b04/html5/thumbnails/7.jpg)
Method
• 11 land hermit crabs • Starved for 4 days prior to study• Testing done in evenings with overhead lights
off• 1 red lamp between two testing tanks• Tanks divided into three zones
![Page 8: Food preference in land hermit crabs ( Coenobita sp.) when given choice of meat or vegetables](https://reader035.vdocuments.mx/reader035/viewer/2022081503/56816612550346895dd95b04/html5/thumbnails/8.jpg)
![Page 9: Food preference in land hermit crabs ( Coenobita sp.) when given choice of meat or vegetables](https://reader035.vdocuments.mx/reader035/viewer/2022081503/56816612550346895dd95b04/html5/thumbnails/9.jpg)
Method
• Hamburger, chicken, ham, and tuna in meat zone
• Spinach, carrot, lettuce, asparagus in vegetable zone
• Crabs were placed in center of tank and gave them 2 minutes for acclimation
• Observed for 15 minutes, recording location every minute
![Page 10: Food preference in land hermit crabs ( Coenobita sp.) when given choice of meat or vegetables](https://reader035.vdocuments.mx/reader035/viewer/2022081503/56816612550346895dd95b04/html5/thumbnails/10.jpg)
Method
• Individual trials once with each crab
• 4 group trials
• Cleaned tank between each trial
• Switch food to opposite ends for half of trials
![Page 11: Food preference in land hermit crabs ( Coenobita sp.) when given choice of meat or vegetables](https://reader035.vdocuments.mx/reader035/viewer/2022081503/56816612550346895dd95b04/html5/thumbnails/11.jpg)
Results
Figure 1: Mean percent time spent in each tank section across 11 individual hermit crab trials (n=11). Each trial lasted 15 minutes.
![Page 12: Food preference in land hermit crabs ( Coenobita sp.) when given choice of meat or vegetables](https://reader035.vdocuments.mx/reader035/viewer/2022081503/56816612550346895dd95b04/html5/thumbnails/12.jpg)
Results
Figure 2: Mean percent time spent in each tank section across 4 group trials (n=11). Each trial lasted 15 minutes.
![Page 13: Food preference in land hermit crabs ( Coenobita sp.) when given choice of meat or vegetables](https://reader035.vdocuments.mx/reader035/viewer/2022081503/56816612550346895dd95b04/html5/thumbnails/13.jpg)
Results
Table 1: Results of chi square test for differences in percentage of time spent in each zone (meat, no food, vegetable) Critical value 5.99.
![Page 14: Food preference in land hermit crabs ( Coenobita sp.) when given choice of meat or vegetables](https://reader035.vdocuments.mx/reader035/viewer/2022081503/56816612550346895dd95b04/html5/thumbnails/14.jpg)
Discussion
• More time was spent in the vegetable zone than meat zone for individual and group trials
• Did not support our first hypothesis (choosing meat over vegetables)
• Did support our second hypothesis (social foraging)
![Page 15: Food preference in land hermit crabs ( Coenobita sp.) when given choice of meat or vegetables](https://reader035.vdocuments.mx/reader035/viewer/2022081503/56816612550346895dd95b04/html5/thumbnails/15.jpg)
Discussion
• Non-significance likely due to no food zone
• Different species of crab than previous studies
• Negative preference induction
• Vegetables easier to ingest quickly
• Benefits of social foraging
![Page 16: Food preference in land hermit crabs ( Coenobita sp.) when given choice of meat or vegetables](https://reader035.vdocuments.mx/reader035/viewer/2022081503/56816612550346895dd95b04/html5/thumbnails/16.jpg)
Questions?